2. Galileo Galilei - (born February 15, 1564 in Pisa, died on January 8, 1642 in Arcetri) -
Italian astronomer, astrologer, mathematician, physicist and philosopher, precursor of
modern physics.
3. General informations
He was born in Pisa. His father, Vincenzo Galilei, was a music theoretician, composer
and wool merchant and his mother was Giulia Ammannati. Galileo was the oldest
child in the family. The name Galileo came from his ancestor (Galileo Bonaiuti), who
was a well-known politician, physician and lecturer at the beginning of the 15th
century - at the same time the family changed their name to Galilei.
In 1589 he became a lecturer in mathematics at the University of Pisa. Then in 1592
he moved to the University of Padua, where until 1610 he lectured on geometry,
mechanics and astronomy. In later life, he developed the scientific method through
numerous experiments and observations.
Galileo, on the basis of his observations, became convinced of the validity of
Copernicus' heliocentric theory at the time when the Church defended the geocentric
theory.
He has never got married, but he had three children with Marina Gambą: daughters
Virginia (born 1600) and Livia (born 1601) (who became nuns) and son Vincenzia
(born 1606).
5. Physics
His very important discovery was the discovery of the phenomenon of inertia. It
overthrew one of the old erroneous beliefs, because for centuries it was thought that if no
other bodies act on the body or if these interactions are "canceled", it can only remain at
rest, and moving at a constant speed must have a cause in the form the impact of other
bodies or body. Seemingly this view is justified by everyday observations. However, by
performing various experiments, Galileo came to the conclusion that the body, which due
to the action of other bodies was given a certain speed, should constantly move in a
uniformly rectilinear motion. He proved that the lower the friction, the less noticeable is
the decreasing speed. He drew the conclusion that if there was no friction, the body set in
motion would move further at a constant speed. Galileo made the first attempt to measure
the speed of light and asked his student and secretary Torricelli to deal with the problem of
not being able to pump out the water in the suction pumps to a height of more than 10
meters. Torricelli did his task by conducting experiments with a mercury submerged at one
end, which showed the existence of atmospheric pressure and became the basis for the
construction of the mercury barometer.
6. Astronomy
In 1609, Galileo was one of the first to use the telescope to observe stars, planets and
the moon. He discovered sunspots, Saturn's rings, and noticed that the Milky Way
consists of very many stars. Observing the Moon, he noticed bright spots on his unlit
part. On January 7, 1610, he discovered the moons of Jupiter - Io, Europa, Callisto; On
January 11, 1610, he discovered another moon of Jupiter - Ganymede. Galileo's
astronomic discoveries were of epochal importance - they were an important
contribution to the Copernicus theory's victory and enabled further development of
observational astronomy (though Galileo himself in many cases disagreed with new
views, e.g. he did not accept the discovery of elliptical orbits of planets by Johannes
Kepler).
7. Techonology
In the years 1595-1598, Galileusz perfected the "Geometric and military compass"
suitable for use by surveyors and military. With its help, you could more accurately set
the gun to the shot and calculate the right amount of gunpowder for firing a cannonball.
Around 1606-1607 he constructed a thermometer. He used the dependence of body
density on temperature. In 1610, using a part of the telescope, he constructed an
improved microscope. He also left many designs of inventions that he did not realize,
such as a combined candle with a mirror for reflecting light inside the building, a fruit-
picking device and a pen-like writing device, and many more.
8. Galileo is the patron of many scientific institutions (especially those related to
astronomy) and social institutions. His name bears also one of the masonic lodges in
Poland. From November 24, 1961, the street in Warsaw, in the present Bemowo
district, is called Galileusz street.
